Quick-freeze method and apparatus



Jan. 20, 1953 R. M. MAGNUSON 2,625,805

QUICK-FREEZE METHOD AND APPARATUS Filed May 13, 1950 Ermentor El Pas M Mnc/vuso/v Wfm Gttorneg Patented Jan. 20, 1953 UNITED STATES PATENT OFFICE I 2,625,805 QUICK-FREEZE METHOD AND APPARATUS Roy M. Magnuson, Campbell, Calif.

Application May 13, 1950, Serial No. 161,796

Claims.

The present invention relates to quick freeze methods and apparatus, and more particularly to methods and apparatus which provide for improved heat transfer conditions within a package of products to be frozen, Such as peaches, peas, beans, ice cream, and the like. The invention is concerned more particularly with the application of intermittent pressure to the package to promote movement of the air and other contents of the package during the freezing operation to enhance heat transfer, in combination with, in certain instances, an intermittent motion of the package without changin its plane of position so as to produce a surging of the liquid or other contents in the package for a greater area of contact of material with the walls of the package during the freezing operation.

The above and other objects of the invention are attained as disclosed in a preferred embodiment of the invention, as illustrated in the accompanying drawings, in which:

Figure l is a plan view of quick freeze apparatus capable of carrying out the invention.

Figure 2 is a sectional elevational view taken as indicated by the line 2-2 in Figure 1.

In quick freeze operations, particularly with material of a more or less granular character, such as peas, for example, or material packed in liquid, such as peaches and the like, one of the principal difficulties in performing the quick freeze operation is the difficulty of heat transfer from within the package outwardly to the walls of the package for transmission to the refrigerating medium, this disadvantage being considerably increased where the packages are held between stationary freezing plates or where the packages are progressed at a uniform rate with respect to or with the freezing surfaces.

In accordance with the instant invention, the packages of articles to be frozen are progressed in intermittent stop-and-go fashion with respect to one or more freezing surfaces and the freezing surfaces themselves are utilized in transmitting a pulsating pressure to the packages while they are stationary. Also, the intermittent stopand-go movement of the packages causes a movement or agitation of the contents and, in case of liquid contents, surging of the liquid to insure contact of the liquid with all surfaces of the package thereby enhancing the rate of heat transfer from within the package to the refrigerating medium.

In the drawings, there is schematically illustrated an apparatus capable of carrying out the above steps in the freezing method disclosed here-- in and referring to Figures 1 and 2 there is shown a base plate it on which there is supported by means of respective frame pieces H a pair of rectangular elongated tanks H which contain a refrigerating medium. Respective inlet and outlet pipes or tubes 13 and M are connected to each tank l2 to provide for circulation of a suitable refrigerating medium, such as brine therethrough. Preferably the bottom surfaces of the tanks R2 are arcuate as shown at l2a and these tanks i2 are supported for in-and-out sliding movement with respect to a series of packages It carried by a flight-type conveyor l! which serves to progress the packages intermittently between the opposed freezing surfaces provided by the tank If. The drive for the conveyor I! is provided through a shaft it from a drive mechanism It incorporating suitable Geneva drive mechanism for supplying an intermittent stop-and-go movement to the conveyor ll, and consequently of the packages $6, with respect to the opposed freezing surfaces related thereto.

Preferably means is provided to apply pressure to the packages It by movement of the freezing tanks l2 and for this purpose adjacent each end each of the chambers I2 is provided with respective sets of connecting rod arms 2| engaged by respective eccentrics 22 carried on a shaft 23. The shafts 23 are suitably journalled for sliding movement on the frame pieces II. The shaft 23 is journalled in a boss 24 of a second connecting rod 26 having its opposite end engaged with an eccentric 21 on a drive shaft 28. The drive shaft 28 is driven cyclically in stop-and-go fashion through a suitable chain and sprocket mechanism 29 from the drive mechanism It so that the tanks [2 are moved inwardly to engage and apply pressure to the packages l5 while they are at rest and are withdrawn (as seen in Figure 2) to free the packages for their forward movement under control of conveyor l1.

Each shaft 23 is driven through a suitable chain and sprocket mechanism 30 from a suitable electric motor 3| providing a relatively rapid rotation of the shafts 23. The throw of the eccentrics 22 is such that a relatively rapid pulsating pressure is applied to the side walls of the packages l6 to be transmitted to the contents of the packages. If desired, the drive for these pulsating eccentrics 22 may be made con tinuous or may be made intermittent so that the pulsation are applied only during the time the tanks l2 are engaged with the packages l6.

While the packages l6 are shown as being rectangular, it is obvious that other shapes, such 3 as cylindrical, can be employed with appropriate shaping of the adjacent surfaces of the tanks [2.

From the above description, it will be seen that as the packages l6 are progressed from the feed end to the discharge end of the equipment, they are intermittently moved in stop-and-go fashion and while they are at rest they are engaged by the freezing tanks l2 so that pressure is applied to the package to insure a good heat transfer contact. At the same time the tanks l 2 are subjected to a pulsating or vibrating action which is correspondingly transmitted to the packages and their contents. This rapid pulsation or vibration of the package and contents moves the articles within the package and any liquid therein about so that they constantly present new surfaces to each other for heat transfer. Also, because this occurs when pressure is being applied to the packages, a maximum effective heat conductivity is attained to further facilitate the freezing operation. V

The stop and go motion .of the packages, particularly any such packages or containers having a fluid content, promotes better heat transfer conditions by causing a surging of any fluid within the package or produces a greater area of contact between the contents of the package and the walls of the package and also cause movement of the fluid or other contents with respect to any wall of the package to break up zones of insulation which may have built up and by such movement to promote a more efficient heat transfer.

While I have shown and described a preferred embodiment of the invention, it will be understood that the invention is capable of variation and modification from the form shown so that its scope should be limited only by the scope of the claims appended hereto.

I claim:

1. A method of freezing packages of material that comprises advancing a package in stop-andgo fashion with respect tov a freezing surface, applying the freezing surface to the package each time the package is at rest, and applying a pulsating pressure effect to the package while it is engaged with the freezing surface.

2. A method of freezing packages of material that comprises advancing a package in stop-andgo fashion with respect to a freezing surface, applying the freezing surface to the package each time the package is at rest, and applying a pulsating pressure effect to the package and to the material therein.

3. A method of freezing packages of material that comprises advancing a package in stop-andgo fashion with respect to a freezing surface, applying the freezing surface to the package each time the package is at rest, and agitating the package and its contents.

4. A method of freezing packages of material that comprises advancing a package in stop-andgo fashion with respect to a freezing surface, effecting a pressure application of the freezing surface to the package while the package is at rest, and rapidly varying the amount of pressure to agitate the package and its contents.

5. A method of freezing packages of material that comprises advancing a package in stop-andgo fashion with respect to a freezing surface, effecting a pressure application of the freezing surface to the package while the package is at rest, and applying a pulsating effect to the package and its contents during said application of pressure thereto.

ROY M. MAGNUSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,998,431 Birdseye Apr. 23, 1935 2,283,923 Hall May 25, 1942 2,532,633 Magnuson Dec. 5, 1950 

